Carpets are typically constructed from a primary backing material and a face pile formed on one side. Face pile can be form in the primary backing by tufting a face pile in the primary backing. Currently, the majority of carpet manufactured in the U.S. is made by a tufting process. The tufting process forms looped or cut pile on one side of a primary backing and loop backs on the opposite side by a process well known in the art. The primary backing can be made from a woven or nonwoven fabric of natural or synthetic materials.
After the primary backing is tufted, an adhesive precoat may be applied to lock or bind the tufts in the primary backing. Typically, the adhesive precoat is an aqueous polymer dispersion, such as a styrene butadiene aqueous polymer dispersion. The aqueous polymer dispersion-coated primary backing is then heated to remove the water from the aqueous polymer dispersion and the polymer locks or binds the tuft loops in the primary backing. Then, a secondary backing may optionally be adhesively attached by applying a coating of adhesive on the side of the primary backing opposite the face pile. Such adhesive is typically a latex, a polyurethane or a hot melt adhesive. Then, a secondary backing is brought into intimate contact with the uncured polyurethane or the molten hot melt adhesive. The adhesive is then allowed to cool or cure, thereby adhesively attaching the secondary backing to the tufted primary backing.
It would be desirable to both achieve tuft lock and to attach a secondary backing to a tufted primary backing of a carpet using a single adhesive system. It would also be desirable to both achieve tuft lock and attach a secondary backing to a tufted primary backing of a carpet using reduced amounts of adhesive without sacrificing desired physical properties of the finished product. Additionally, it would also be desirable to both achieve tuft lock and attach a secondary backing to a tufted primary backing of a carpet in a more energy efficient manner.